This invention pertains to a breakaway support system for signs, and particularly to an omni-directional breakaway system for supporting ground mounted signs located within zones that are vulnerable to vehicular impacts.
Accident research and field experience have demonstrated that vehicles often leave the roadway and impact structures at high angles of incident. Breakaway sign posts have proven to be highly effective in reducing vehicle damage and occupant injury resulting from collision with highway marker signs. A variety of breakaway sign post constructions intended to meet safety requirements for highway installations have been used before for installation of highway traffic signs.
Conventional breakaway systems are typically used between a relatively short section of base post that is set in a concrete base in the ground, and a longer section of sign post that extends upwardly above the ground from the base post and supports the sign. When a car collides with the sign post, the section of the sign post above the ground is typically sheared off or hinged over to allow the car to continue on its path with minimum damage to the vehicle and without injury to its occupants. Laws and regulations typically require that the base post extend no more than a few inches above the ground following a collision to avoid damage to fuel lines or penetration of the vehicle passenger compartment as the vehicle passes over the broken-off posts.
It is important that a predictable and reliable breakaway attachment be provided between the post sections to insure that the sign post will break without imparting excessive force to the car or causing injury to its occupants, and to insure that the stub height of the base post does not cause damage to the vehicle as the vehicle passes over the base post following a collision. It is also important that such sign posts be capable of withstanding ambient wind loads normally encountered by highway sign installations. What is further needed is a breakaway attachment that provides for a predictable and omni-directional break regardless of the direction or angle of impact.